I remember running my 500 Morini with no header pipes (V twin) all you heard was crack crack crack and blue flame popping out of the head at idle - was really cool. Then I ran the BMW 1000cc boxer with just the header pipes OH MY G O D you don't want to do that. The Geo sounds pretty cool at certain speeds and really nice without the resonator just after the cat - gives it a little throaty snarl.